ors-amarisoft: drop ru_type and ru_link_type

  Use key/object structure instead const, since it provides better struture whenever render the form.

  It is required to still update instance for follow up the change

software/ors-amarisoft/ru/sdr/input-schema.json

@@ -20,11 +20,6 @@
           ],
           "properties": {
             "$ref": "../../ru/common.json#/properties",
-            "ru_link_type": {
-              "$ref": "#/properties/ru_link_type",
-              "const":    "sdr",
-              "default": "sdr"
-            },
             "sdr_dev_list": {
               "title": "SDR boards",
               "description": "Which SDR boards to use as combined RF port",